Britney Spears's First Post-Rehab Outing

In her first public appearance since rehab, Britney Spears stepped out to take a dance class and have a sushi dinner with her girlfriends.

Spears left home Friday night to take a one-hour hip-hop class at the Millennium Dance Complex in North Hollywood – this after lying low since checking out of Malibu's Promises treatment facility on Tuesday.

Wearing nude fishnet stockings with dance boots, black hot pants, a black long-sleeved shirt and a baseball cap over her dark brown wig, Spears arrived with her assistant as well as two bodyguards to take a 7 p.m. advanced-level hip-hop class with instructor Darrien Henning.

"The minute she walked in, she basically lit up the room," Henning told PEOPLE. "I had no idea she was coming, so I was shocked."

Spears, whom Henning described as looking "fantastic," quietly took a spot in the back of the about 30-person class held at the studio's 12,000-sq.-ft. "Dome." "She did the choreography really well," Henning said, adding, "In fact, she came in and nailed it."

And the pop star's presence in class seemed to serve as an inspiration: "All my students tried harder to get on their game," Henning said.

Returning to the dance studio is a homecoming of sorts for Spears, says Millennium Dance Complex owner Robert Baker, who counts Spears as one of his star clients. "She also comes in to scope talent," he told PEOPLE. "More than once she's hired our teachers to choreograph for her."

And true to form, she stuck around after class to watch a master class from the VIP lounge.

Spears next headed to Bel Air fusion Japanese eatery SHU Sushi House Unico to meet up with three girlfriends at around 10 p.m. The four women dined at a table near a window at the front of the restaurant, an onlooker tells PEOPLE.

Upon leaving, Spears smiled at waiting photographers and gave a friendly wave before heading home alone at about 11:30 p.m.

On Sunday, Spears made another outing – this one presumably not as much fun. She paid a visit to a Los Angeles hospital to see a dentist, her rep tells PEOPLE.